I packed for a 7-day cruise with just a carry-on. This item was a total waste of space.
Packing for a cruise can be stressful for some. Maybe you've combed through every packing list you can find but are still worried about packing the wrong attire of forgetting something important. This can be especially true for first-time cruisers, or even if you are trying a new-to-you cruise line.
To keep things simple, I almost exclusively travel with just a carry-on, even for 7-night cruises. I find that this simplifies my travel immensely.